Word Origin & History

Rubicon in phrase "to cross (or "pass") the Rubicon "take a decisive step," 1626, in ref. to small stream to the Adriatic on the coast of northern Italy, which in ancient times formed part of the southern boundary of Cisalpine Gaul; crossed by Caesar Jan. 10, 49 B.C.E., when he left his province to attack Pompey. The name is from L. rubicundus "ruddy," in ref. to the color of the soil on its banks.